Supporting and loading arm for the drawing mechanism of a spinning machine



Oct. 18, 1966 F. ,STAHLECKER ETAL 3,273,994

SUPPORTING AND LOADING ARM FOR THE DRAWING MECHANISM OF A SPINNING MACHINE Filed Dec; 27,1963 4 Sheets-Sheet 1 I a 2 2' a 1 N 111 1;;L/ I

v I l V I L 6 2 g I f A 6 202 5 7 5 5 6 5 a a K INVENTORS BY 0M7 ATTORNEYS Oct. 18, 1966 F. STAHLECKER ETAL 3,278,994

SUPPORTING AND LOADING ARM FOR THE DRAWING V MECHANISM OF A SPINNING MACHINE Filed Dec. 27, 1963 4 Sheets-Sheet 2 405 405 405" (adv/40a 400 Fig 5 K;

Q r I l 42 4/ INVENTORS BY C ATTORNEYS Oct. 18, 1966 F. STAHLECKER ETAL 3,273,994

' SUPPORTING AND LOADING ARM FOR THE DRAWING I MECHANISM OF A SPINNING MACHINE Filed Dec. 27, 1965 4 Sheets-Sheet 5 119i as 804 82 as a;

INVENTORS FRITL QTHHL'CkE Q SIG/mule Kennacn ATTORNEYS Oct. 18, 1966 F. STAHLECKER ETAL 3,273,994

SUPPORTING AND LOADING ARM FOR THE DRAWING MECHANISM OF A SPINNING MACHINE 4 Sheets-Sheet 4 Filed Dec. 27, 1963 INVENTORS FR/rz. STHHLEiL/(ER GMu/VO KEMMLiR ATTORNEYS United States Patent 3,278,994 SUPPORTING AND LOADING ARM FOR THE DRAWING MECHANISM OF A SPINNING MACHINE Fritz Stahlecker, Bad Ueberkingen, Wurttemberg, and Sigmund Kemmler, Geislingen, Steige, Wurttemberg, Germany, assignors to Spindelfabrik Siissen, Schurr, Stahlecker & Grill G.m.b.I-I., Sussen, Wurttemberg, Germany Filed Dec. 27, 1963, Ser. No. 333,830 Claims priority, application Germany, Dec. 29, 1962,

3,102 7 Claims. (Cl. 19281) The present invention relates to a supporting and loading arm for the drawing mechanism of a spinning machine which is provided with centrally supported pressure rolls and a U-shaped guide rail in which a guide bracket for each pressure roll is adjustably mounted in the longitudinal direction of the guide rail and adapted to be locked in the adjusted position, and which bracket engages with the lateral sides of the guide rail and is provided in its end with a guide recess for receiving pressure roll and with .a spring for exerting the required pressure upon the pressure roll.

There are supporting and loading arms for drawing mechanisms already known in which the pressure rolls in the form of twin rolls which are centrally supported are held in special guide elements. These guide elements are provided in the form of arms or of bearing members which are slidably guided in housings so as to be movable in a direction substantially vertical to the drawing plane. It has also been proposed to guide the centrally mounted upper rolls in recesses in guide brackets which are guided and secured in a U-shaped guide rail, and to provide several loading springs for each pressure 'roll, that is, one coil spring directly in front and another coil spring directly behind the shaft of each pressure roll on the aforementioned bracket. These guide brackets for the upper rolls are accordingly designed so as to be substantially symmetrical with reference to a plane extending through the axis of the pressure roller and vertically to the drawing plane.

The known types of supporting and loading arms in which the pressure rolls are held by guide arms have considerable disadvantages. When the supporting and loading arm is pivoted upwardly to the inoperative position or pressed downwardly to the operative position, the pressure rolls are shifted to some extent in the longitudinal direction relative to the lower rolls, that is, in the direction in which the yarn is moving. This may impair the quality of the yarn and lead to thread breakage. If such guide arms are provided in the form of so-called pendulum arms, there is no assurance that the axially parallel position of the upper rolls to the lower rolls will be maintained, especially as far as the first and central rolls are concerned and when synthetic fibers are being worked upon. The application of the load upon such guide arms in the conventional manner from above through springs produces laterally acting force components which likewise impair the axially parallel position of the rolls and cause undesirable frictional forces. Although efforts have been made to overcome these disadvantages of the known types of supporting arms, these efforts were only partly successful and resulted in rather complicated constructions. The known types of bearing members in which the pressure rolls are held and which are slidable in housings in a direction substantially vertical to the drawing plane do not insure that the pressure rolls will always be accurately parallel to the lower rolls since the guide surfaces of the housings in the recesses of the supporting arm are relatively short and the bearing mem-' ice bers are guided in the housings merely by pins and slots. The guiding of each housing in the supporting arm and the guiding of the bearing member in the housing could be improved only by enlarging the housing and bearing member both vertically and in length. This is, however, impossible because it would then no longer be possible to adjust the pressure rolls to the small distances between them which :are required in such drawing mechanisms.

The same applies to the known types of slide brackets with guide recesses for the pressure rolls and with coil springs in front of and behind the shafts of the rolls. The coil springs of these devices can also not be made as large as would be necessary to attain the very strong loading pressures as are nowadays required since there would be ins-ufi'icient space available to adjust the pressure rolls to the required short distance from each other.

It is an obgiect of the present invention to overcome the above-mentioned disadvantages by providing the slide bracket with at least one arm which extends in an oblique downward direction toward the front and/or toward the rear and engages with the guide rail near the lower edges of the latter, and by providing on the bracket a leaf spring which extends substantially parallel to the mentioned arm and the free end of which presses upon the shaft of the associated pressure roll.

In order to be able to make these bracket arms .as well as the leaf springs as long as possible, the invention provides that these arms are downwardly inclined so that the adjacent bracket arms when located close to each other will overlap each other like roof shingles. The bracket arms are then preferably laterally guided in the U-shaped guide rail along a length, as seen in the direction of the drawing plane, which is .at least 1.3 times as long as the smallest possible distance between two adjacent pressure rolls on guide brackets of equal length. A guide bracket of a very suitable and simple shape which takes up very little space may be attained by making it of sheet steel and by making its downwardly inclined part of a U -shaped cross section so as to form two lateral arms, and by mounting the leaf spring so as to extend substantially between these arms. For reasons of a more simple construction it is then advisable to bend the two arms slightly outwardly before the guide bracket is installed so that, after it is installed, these arms will be resiliently bent and engage with a light pressure against the sides of the U- shaped guide rail. Instead of such engagement of the bracket arms substantially along their entire length with the sides of the guide rail, it is also possible to provide the bracket arms with outwardly punched projections which engage with the sides of the guide rail.

The leaf spring is designed so as first to follow the general oblique direction of the bracket arm, and its extension then presses directly or indirectly upon the shaft of the pressure roll. In order to provide a relatively long leaf spring and accommodate the same substantially between the side walls of the bracket arm, even though these side walls have a relatively small width or height, it is advisable to bend the free end of the leaf spring downwardly and back to form a hook and to use this hookshaped end to press upon the shaft of the pressure roll. According to another feature of the invention, the leaf spring may be suspended so as to have a three-point support. Two of these points are formed by abutments which are located near the secured end of the guide bracket and at least one of which is vertically adjustable,

. while the third point of support is formed by the direct or indirect engagement of the free end of the leaf spring on the shaft of the pressure roll. The adjustable abutment may be formed by a setscrew which is adjustable from above. Another feature of the invention is to render this adjustable setscrew foolproof by providing it with a special cover which hides it and thus prevents it from being turned by an unauthorized person who is not familiar with the device. This cover is loosely held in position near one end by the bolt which secures the associated guide bracket to the U-shaped guide rail, while its other end is provided with a small projection which engages into a slot of the guide rail. Thus, when the guide bracket is secured in a fixed position, the setscrew can be reached only by bending the slightly resilient cover up wardly to lift the projection out of the slot in the guide rail and by then turning the cover toward one side about the bolt. Such a cover may in addition be provided with a suitable marking for indicating the position of the guide bracket and for facilitating an accurate adjustment of this position relative to the guide rail. The marking on the cover may for this purpose be associated with a scale which is marked on the guide rail.

The arms of the guide brackets of the supporting and loading arm according to the invention may extend either in the direction toward the first or feed roll or toward the last or delivery roll. The obliquely inclined shape of the bracket arms according to the invention not only permits these arms to be mounted so as to overlap each other so that the adjacent pressure rolls may be spaced at a very small distance from each other but it also permits the adjacent pressure rolls to be spaced at a very large distance from each other by mounting the adjacent brackets so that their arms extend in opposite directions. It is thus possible to employ relatively short supporting and loading arms and still to attain a very large distance between the adjacent pressure rolls. This arrangement has the further advantage that a large free area is attained on the lateral walls of the guide rail underneath and between two adjacent bracket arms which extend in opposite directions. This area may be employed for mounting additional supporting or guide elements for further parts of the drawing mechanism which may consist, for example, of self-loaded rolls as employed especially for treating materials of a long staple length, or of clearer rolls or similar devices or of belts. The additional supporting or guide elements for such further parts of the drawing mechanism may also be provided directly on the arms of the guide brackets.

The locking spring which prevents the pressure roll from falling out of the guide recess in the end of the bracket arm when the supporting and loading arm is pivoted upwardly to the inoperative position is preferably mounted on the bracket arm, especially if the latter is made of sheet steel, by providing both side walls of the U-shaped bracket arm near the recessed end with tabs which are bent at a right angle to the surfaces of these side walls and which permits the locking spring to be securely hooked thereon in a very simple manner. The locking spring may then also serve additionally as a means for mounting the clearer roll.

Since modern methods of construction now permit drawing mechanisms to be equipped with upper and lower rolls of a very accurate cylindrical shape and trueness, the guide recesses on the arms of the guide brackets will fully comply with all requirements. Generally, it is therefore suflicient to mount the shafts of the pressure rolls directly in the very accurately made recesses in the bracket arms without specially reinforcing the walls of these recesses. In certain cases it may, however, be advisable to provide these walls with a special surface so as to have improved gliding properties, for example, by providing a lining of nylon or similar material thereon. A similar effect may also be attained by providing a separate bearing member with special antifriction properties which is slidable along the normal untreated walls of the guide recess and fits over and guides the shaft of the pressure roll.

The features and advantages of the present invention will become more clearly apparent from the following detailed description thereof which is to be read with reference to the accompanying drawings, in which:

FIGURE 1 shows a side view, partly in section, of a supporting arm with a U-shaped guide rail and two cast guide brackets with tightly clamped leaf springs thereon;

FIGURE 2 shows a cross section which is taken along the line IIII of FIGURE 1;

FIGURE 3 shows a cross section which is taken along the line HIIII of FIGURE 1;

FIGURE 4 shows a view similar to FIGURE 1 of a supporting arm according to a modification of the invention which is provided with two U-shaped guide brackets of sheet metal and setscrews for adjusting the pressure of the leaf springs;

FIGURE 5 shows a top view of the supporting arm according to FIGURE 4;

FIGURE 6 shows a cross section which is taken along the line VIVI of FIGURE 4;

FIGURE 7 shows a detail view of the guide bracket, per se according to FIGURE 4;

FIGURE 8 shows a view similar to FIGURE 1 of a supporting arm according to another modification of the invention which is provided with a pair of guide brackets with elbow-shaped bracket arms and leaf springs and with a special lining for the walls of the guide recesses for the pressure rolls;

FIGURE 9 shows a front view, partly in section, of the supporting arm according to FIGURE 8 and asseen in the direction of the arrow 1X therein;

FIGURElO shows another View similar to FIGURE 1 of a supporting arm according to a further modification of the invention;

FIGURE 10a shows a detail view of the upper part of the guide bracket according to FIGURE 10 and as seen in the direction of the arrow X therein;

FIGURE 11 shows a top view of a part of the supporting arm according to FIGURE 10; while FIGURE 12 shows a diagrammatic side view of a sup.- porting arm according to a further modification of the invention which .is provided with three guide brackets, two of which are mounted so as to extend in opposite directions to each other.

Referring first to FIGURES 1 to 3 of the drawings, the guide rail 1 has a U-shaped cross section and carries the guide brackets 3 which are made by being cast or molded and are secured to guide rail 1 by bolts 2 and nuts 2 so as to be adjustable in the longitudinal direction of guide rail 1. The free ends of the oblique arms .4 of brackets 3 are provided with guide recesses 5, the side walls of which extend substantially vertically to the drawing plane EE. In these recesses 5 the bearing members 6 are guided which hold the shafts 7 of the twin pressure rolls 8, 8'. Each shaft 7 is pressed in a downward direction by a leaf spring 9 which is likewise secured by the bolt 2 and nut 2 to the guide bracket 3, and extends substantially in the direction of the arm 4 of bracket and presses with its free end upon the bearing member 6 and through the latter upon shaft 7. Guide rail 1 forms in the conventional manner a part of a supporting and load arm which is pivotably mounted at one end, not shown, on a supporting rod. When in the operative positron, this supporting arm is held in a certain location relative to the drawing plane E-E in which the leaf springs 9 press the pressure rolls 8, 8' with a certain pressure upon the lower rolls 10. When the supporting arm together with guide rail 1 is lifted off the lower rolls 10, leaf springs 9 press the pressure rolls 8, 8' through the bearing members 6 so far downwardly in the guide recesses 5 until they engage upon the stop pins 201 which are mounted on the arms 4. The bearing members 6 are then prevented by locking springs 202 from falling out of the guide recesses 5. Each of these locking springs 202 is secured to the associated leaf spring 9 and extends between the two wall portions 5' and 5" which define each guide recess 5, and the free end 202'of this spring 202 forms a book which projects underneath the bearing member 6.. Each of the pressure rolls 8, 8"can therefore be removed from or reinserted into the associated bearing member 6 only when the supporting and load arm is pivoted upwardly and when the free end 202' of locking spring 202 is pulled back. As indicated in FIGURE 2 the width of leaf spring 9 decreases toward its free end which presses upon the pressure roller shaft so as to permit this end to be inserted between the walls 5, 5" of the guide recess 5 and to engage upon the bearing member 6. FIGURE 3 shows the manner in which the bearing member 6 is held in the guide recess 5 and that the shaft 7 of the pressure rolls is held for a considerable length in the bearing member 6. Guide bracket 3 is guided by the lateral surfaces 3' of its upper part along the side walls 1', 1" of guide rail 1 and also by the lateral surfaces 5" of the end of the bracket containing the guide recess. It is therefore guided along the greatest part of its length which insures that the accurate position of each guide bracket in :the guide rail and thus also the accurate position of each pressure roll 8, 8 parallel to the axis of the associated lower roll 10 will be maintained at all times. Despite the considerable length of the guided part of each guide bracket 3 in guide rail 1, it is possible to move the adjacent guide brackets very closely to each other so that the adjacent pressure rolls may also be located at a very short distance from each other. The inclined arms of the adjacent guide brackets then overlap each other like the shingles on a roof.

The supporting arm as illustrated in FIGURE 4 comprises a guide rail 41 in which a pair of guide brackets 43 consisting of sheet steel are secured by bolts 42 and nuts 42 so as to be adjustable in the longitudinal direction of the guide rail. The downwardly inclined bracket arms 44 and 44" are bent so as to have a U-shaped cross section, as shown in FIGURES 6 and 7, and are provided with guide recesses 45 in their free ends. The wall surfaces 45 and 45" of these guide recesses may be easily made so as to be in accurate alignment with each other so that the shaft 47 of the respective pressure roll 48 and thus the pressure roll itself will extend exactly at right angles to the long bracket arms 44' and 44 and the pressure roll will extend exactly parallel to the associated lower roll. This, however, requires the central plane of the supporting arm or the guide rail to extend exactly vertically to the lower rolls which may be effected without difficulty with modern methods of production and assembly. The wall surfaces 45, 45 of guide recesses 45 may be tempered. Each leaf spring 49 is pivotably mounted at its upper end on a pivot pin 403 at a short distance from bolt 42, and during the operation of the drawing mechanism the leaf spring engages with a setscrew 404 which is screwed through the nut 42' and projects through the slot 41 in the guide rail and through a bore in the cover 405. This cover 405 serves as a washer for the bolt 42 and also covers a considerable part of slot 41, as shown in FIGURE 5. One of its edges 405' or 405" or 405" serves as a marking for indicating and adjusting the position of the guide bracket and thus the position of the associated upper roll relative to the guide rail 41 in the direction of the drawing plane. Guide rail 41 is for this purpose provided with a scale 41". Setscrew 404 as well as bolt 42 are accessible from above when the cover 406 of the supporting arm which covers the guide rail is removed.

Cover 406 may also form a part of a locking or relieving lever, not shown, or be adjustably or removably connected thereto. Setscrew 404 has a cylindrical end 404 which only engages at one point of its outer edge upon the leaf spring which extends obliquely to the setscrew. This prevents an accidental turning the screw and therefore renders a check nut unnecessary, even though the screw is only held by a few turns of its screw thread in the nut 42. The lowerend of leaf spring 49 is bent over and the bent end 49' acts directly upon the shaft 47 of the pressure roll. Such a leaf spring may be completely inserted between the arms 44' and 44" and has a great effective length. Since the U-shaped guide rail 41 and also the two arms 44' and 44" of each bracket 43 can be economically produced only with a certain tolerance in the inner width between the lateral sides 41" and 41" of the guide rail and in the outer distance between the two arms of the bracket, it is necessary to select a slide member which fits accurately between the sides 41" and 41"" of the guide rail. An accurate guiding of bracket 43 will, however, also be attained in a simple manner if prior to its installation its arms 44' and 44" are slightly spread, as indicated in an exaggerated manner in FIGURE 7. When installed, these arms 44 and 44" press lightly against the sides 41" and 41"" of the guide rail so that the bracket will fit without play into the guide rail but will still be easily slidable along the same. The locking springs 402 and 402 for the pressure rolls 48 are slipped from above over the bent-over parts 45" on the arms 44 and 44" which are substantially in alignment with and closely adjacent to the guide recess 45 (also see FIGURE 7), and they are thus securely connected to these arms. Locking spring 402' is bent over so as to be slightly wider than spring 402, and it also clamps a holder 408 for a clearer roll (not shown) upon the bent-over parts 45".

In the further embodiment of the invention, as illustrated in FIGURES 8 and 9, the guide brackets 83 which are guided in the guide rail 81 are also made of sheet steel similar to the brackets according to FIGURE 4 and are bent to a U shape to have a pair of arms 81' and 81". The upper part 84' of each arm of each bracket extends obliquely downwardly in one direction, while its lower part 84" extends obliquely in the opposite direction and is provided at its free end with the guide recess 85 for holding an upper roll. A guide bracket of such an elbow shape is advisable if these arms should not only be as long as possible so as to be safely guided, but if the point of securement of the upper part of the bracket should also be located at a very short distance from the axis of the associated upper roll, as seen in the direction parallel to the drawing plane. This distance which is indicated in FIGURE 8 by the double arrow a is much shorter than the corresponding distance a in FIGURE 4 in which the side walls of the brackets do not have any angular shape. Leaf springs 89 are made of a shape in accordance with the arms 84, 84" and their lower, substantially horizontal ends engage directly upon the shafts 87 of the pressure rolls. Due to their length, these leaf springs have a very suitable spring action. The arm 85" at one side of the guide recess is provided with a covering 85 of plastic with good sliding properties, for example, nylon, so .as to insure that the shaft of the pressure roll which in operation is pressed against this side will slide easily thereon. This covering 85" may be molded upon the arm 85" in the manner as indicated in FIGURE 8, or it may be removably secured thereto to permit it to be exchanged when worn. As shown in FIGURE 9, the two arms 84' and 84" of the guide bracket do not engage continuously with the sides 81, 81" of guide rail 81, but only at their central and lower parts by means of outwardly pressed surfaces 107 and 108. Thus, each guide bracket is securely guided on the guide rail even though the largest part of its lateral surfaces does not engage with the guide rail. Each supporting arm according to FIGURE 8, however, likewise is provided with a setscrew 804 which is accessible from above and acts similarly as in FIGURE 4 upon the leaf spring, and it is also provided with a stop pin 801 for the leaf spring.

FIGURE 10 shows another modification of the invention in which the guide rail 101 again carries a pair of guide brackets 103 which are made of sheet steel and are adjustable on the guide rail in the longitudinal direction thereof. Each bracket is securely clamped in a fixed position by a bolt 102 and a nut in the .form of a plate 102' into which the setscrew 114 is also screwed which acts upon the leaf spring 109. The second abutment for the leaf spring consists of a downwardly bent lug 119 on the transverse part 103 of bracket 103 which has an aperture 119' with a small tab 119" projecting upwardly from the lower side of this aperture, as clearly shown in FIGURE 10a. This tab 119 engages into an aperture 109' in the end of leaf spring 109 and thus holds the spring securely hooked thereon. The other free end of the leaf spring is again bent back and presses directly upon the shaft 107 of the pressure roll which is guided within the recess 105 in the lower end of the arm of bracket 103. The tapped plate 102' is further provided with a long tapped bore into which a setscrew 114 is tightly fitted which extends substantially vertically to the main part of leaf spring 109. Setscrew 114 is accessible from above through the slot 101 in the guide rail and through a bore in the part 103' of the bracket, but only'when the cover 115 is turned toward one side. This cover 115 is only loosely held in position by bolt 102 since the washer 102" lies on a disk 102" which centers the cover 115 and is slightly thicker than cover 115. On its end, the cover 115 has a small projection which engages into the slot 101' and guides the cover therein. If this resilient cover is slightly lifted, for example, by a screw driver, at the end carrying the projection 115, it may then be turned toward one side even though the bolt 102 has not been loosened. The pressure which is exerted by the leaf spring upon the pressure roll may therefore be adjusted even though the guide bracket is rigidly secured to the guide rail. Since the setscrew 114 is accessible only after the cover 115 has been lifted and turned, an adjustment of the bracket which first requires the bolt 102 to be loosened may be carried out without danger that the setscrew 114 might accidentally also be turned by a person who is not familiar with the construction of the supporting arm. As shown in FIGURE 11, cover 115 is provided with a marking notch 115" which is associated with a scale 101" on the guide rail for indicating and adjusting the position of the guide bracket relative to the guide rail.

The two guide brackets 103 according to FIGURE 10 are shown very closely adjacent to each other in the position in which the pressure rolls 108 and 108' are almost as close to each other as possible. If one of the brackets is reversed so that its arm extends obliquely downwardly in the opposite direction, as indicated in FIGURE 10 in dot-and-dash lines by reference numeral 103", the pressure rolls 108 and 108' will be spaced at a very great distance from each other, even though the two brackets are clamped on the guide rail very closely adjacent to each other. Underneath and between the arms of the adjacent brackets 103 ad 103" a large free area will then be formed on the lateral sides of the guide rail within which additional elements of the drawing mechanism may be mounted. Thus, for example, as indicated in FIGURE 10, a holder 120 for supporting a slip or clearer roll is held by a slot or a projection 120' on these surfaces of the guide rail. The guide rail is provided with further slots or projections 120" and 120' to permit the holder 120 to be mounted at different positions or several holders to be mounted adjacent to each other.

FIGURE 12 shows a complete supporting arm in which, for example, three guide brackets 123, 123', 123" are mounted in a manner so that the pressure rolls will be spaced at the greatest possible distances from each other. In the main drawing area a belt guide is provided. This drawing clearly shows that, despite the great distance between the rolls the supporting arm may be relatively short since the end roll 128 is located in front of the inclined end 121 of the guide rail 121 because of the obliquely projecting arm of the bracket carrying the roller 128, while the first roll 128" is adjusted so as to be located closely adjacent to the locking and pivoting device 129 of the supporting arm without, however, aifecting the easy accessibility of the latter. If the guide bracket 123 which projects from the guide rail is made of sheet steel and its arm is of a U-shaped cross section, its open side is closed by acover 130. The supporting arm is further provided within the area underneath the arms of the guide brackets 123 and 123' with a slide member which is connected to the guide rail and presses a belt upon its support. Furthermore, a roller 131 is supported on the arm of the bracket 123 for tightening the belt.

If the three guide brackets as shown in FIGURE 12 are installed in the supporting arm'so as to extend in the same direction, the pressure rolls may, if desired, be adjusted so as to be spaced at very short distances from each other. In this event, the supporting means for the other elements 130', 131, etc. of the drawing mechanism may be removed in a very simple manner from the guide rail or the guide brackets.

Although our invention has been illustrated and described with reference to the preferred embodiments thereof, we wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the ap pended claims.

Having thus fully disclosed our invention, what we claim is:

1. A supporting and loading arm for the drawing mechanism of a spinning machine comprising an elongated guide rail having an inverted U-shaped cross section with an upper central web and a pair of spaced, substantially parallel lateral webs, a plurality of guide brackets each having an upper connecting part slidably adjustable along said central web and an arm extending obliquely downwardly from said connecting part between said lateral webs and having a free lower end projecting downwardly beyond the lower edges of said lateral webs, each said bracket engaging with and guided by said lateral webs at least near the lower edges thereof, said projecting lower end of each said bracket arm having a downwardly open guide recess therein with parallel side walls extending transverse and substantially vertically to said guide rail, a plurality of twin pressure roll units, each having a shaft centrally between its rolls and inserted into each said guide:

recess and slidable vertically therein and guided by said side walls thereof, and a leaf spring for each bracket" mounted at one end on the connecting part of the corresponding bracket and extending substantially parallel. to said bracket arm between said lateral Webs of said guide rail and pressing with its other end from above upon the roller unit shaft carried by the bracket arm, and means for locking said brackets to said guide rail in different positions longitudinally thereof.

2. A supporting and loading arm as defined in claim 1, in which each said leaf spring is freely suspended on said connecting part and has three supporting points, two of said points forming abutments on said connecting part, means for adjusting at least one of said abutments in .a substantially vertical direction, and the third point formed by the engagement of the free end of said leaf spring with said shaft of said pressure roll unit.

3. A supporting and loading arm as defined in claim 2,

prising an adjustable setscrew screwed from'above through said connecting part and accessible from above through said slot, and a cover of a resilient material on said guide rail and normally covering a part of said slot and saidv setscrew and loosely mounted near one end on said bolt so 1 as to permit said cover to be turned about said bolt when said bolt is tightened, said cover having a projection on its other end normally engaging into said slot, said cover adapted to be resiliently lifted at said other end and thento be turned about saidbolt toward one side so as to uncover the upper end of said setscrew to permit said setscrew to be adjusted.

4. A supporting and loading arm as defined in claim 3, in which said guide rail has a scale marked on its upper side, each said cover having a marking associated with said scale for determining and adjusting the position of each said guide bracket relative to said guide rail.

5. A supporting and loading arm as defined in claim 1, in which two adjacent guide brackets are mounted on said guide rail so that their bracket arms extend in opposite directions to permit the associated pressure roll units on said bracket arms to be located at a considerable distance from each other.

6. A supporting and loading arm'as defined in claim 5, in which additional means are mounted underneath and between said adjacent bracket arms extending in opposite directions.

7. A supporting and loading arm for the drawing mechanism of a spinning machine comprising an elongated guide rail having an inverted U-shaped cross section with an upper central web and a pair of spaced, substantially parallel lateral webs, a plurality of guide brackets each having an upper connecting part slidably adjustable along said central web and an arm extending obliquely downwardly from said connecting part between said lateral webs and having a free lower end projecting downwardly beyond the lower edges of said lateral webs, each said bracket engaging with and guided by said lateral webs at least near the lower edges thereof, said projecting lower end of each said bracket arm having a downwardly open guide recess therein with parallel side walls extending transverse and substantially vertically to said guide rail, a plurality of twin pressure roll units, each having a shaft centrally between its rolls and inserted into each said guide recess and slidable vertically therein and guided by said side walls thereof, and a leaf spring for each bracket mounted at one end on the connecting part of the corresponding bracket and extending substantially parallel to said bracket arm between said lateral webs of said guide rail and pressing with its other end from above upon the roller unit shaft carried by the bracket arm, and means for locking said brackets to said guide rail in different positions longitudinally thereof, said guide brackets being made of sheet steel and having a U-shaped cross section so that each bracket arm has two lateral walls substantially disposed between said lateral webs of said guide rail and engaging with said webs at least near the lower edges thereof, said leaf spring extending substantially between said lateral walls, said two side walls of each of said bracket arms having tabs near the free end of each said arm substantially at right angles to said side walls, and a locking spring connected to said tabs for holding said pressure roll unit within said guide recess when said supporting and loading arm is pivoted upwardly and for also holding a supporting member for an additional element required for the operation of said drawing mechanism.

References Cited by the Examiner UNITED STATES PATENTS 2,675,586 4/1954 Hohloch 19-281 X 2,787,025 4/ 1957 Solanas 19280 2,870,487 1/1959 Dausch l928l X 2,890,495 6/ 1959 Miesch et al 19-281 X 2,893,065 '7/1959 Noguera l9-281 X 2,951,267 9/1960 Noguera 19-28l X 3,015,860 1/1962 Stahlecker 19267 3,076,237 2/1963 Newton 19295 X 3,091,814 6/1963 Huber et al 19-281 FOREIGN PATENTS 1,208,415 9/ 1959 France. 1,232,027 4/ 1960 France.

897,616 5/ 1962 Great Britain.

540,161 3/1956 Italy.

ROBERT R. MACKEY, Primary Examiner. 

1. A SUPPORTING AND LOADING ARM FOR THE DRAWING MECHANISM OF A SPINNING MACHINE COMPRISING AN ELONGATED GUIDE RAIL HAVING AN INVERTED U-SHAPED CROSS SECTION WITH AN UPPER CENTRAL WEB AND A PAIR OF SPACED, SUBSTANTIALLY PARALLEL LATERAL WEBS, A PLURALITY OF GUIDE BRACKETS EACH HAVING AN UPPER CONNECTING PAPT SLIDABLY ADJUSTABLE ALONG SAID CENTRAL WEB AND AN ARM EXTENDING OBLIQUELY DOWNWARDLY FROM SAID CONNECTING PART BETWEEN SAID LATERAL WEBS AND HAVING A FREE LOWER END PROJECTING DOWNWARDLY BEYOND THE LOWER EDGES OF SAID LATERAL WEBS, EACH SAID BRACKET ENGAGING WITH AND GUIDED BY SAID PROJECTING LOWER AT LEAST NEAR THE LOWER EDGES THEREOF, SAID PROJECTING LOWER END OF EACH SAID BRACKET ARM HAVING A DOWNWARDLY OPEN GUIDE RECESS THEREIN WITH PARALLEL SIDE WALLS EXTENDING TRANSVERSE SUBSTANTIALLY VERTICALLY TO SAID GUIDE RAIL, A PLURALITY OF TWIN PRESSURE ROLL UNITS, EACH HAVING A SHAFT CENTRALLY BETWEEN IT ROLLER AND INSERTED INTO EACH SAID GUIDE RECESS AND SLIDABLE VERTICALLY THEREIN AND GUIDED BY SAID SIDE WALLS THEREOF, AND A LEAF SPRING FOR EACH BRACKET MOUNTED AT ONE END ON THE CONNECTING PART OF THE CORRESPONDING BRACKET AND EXTENDING SUBSTANTIALLY PARALLEL TO SAID BRACKET ARM BETWEEN SAID LATERAL WEBS OF SAID GUIDE RAIL AND PRESSING WITH ITS OTHER END FROM ABOVE UPON THE ROLLER UNIT SHAFT CARRIED BY THE BRACKET ARM, AND MEANS FOR LOCKING SAID BRACKETS TO SAID GUIDE RAIL IN DIFFERENT POSITION LONGITUDIANLLY THEREOF. 